The invention relates to conical screw mixers having a mixing screw which runs parallel to and along the inner wall of the product chamber conical screw mixer as initially mentioned serves to mix and process powdery, liquid, or pasty fluids in chemical process technology, in the food industry and in related branches of industry.
The mixing screw, disposed in the interior, rotates about the longitudinal axis and is moved parallel to and along the inner wall in the product chamber. This requires a non-rotational, angularly movable coupling in the bottom area which transmits both the rotation of the mixing screw and the pivotal movement of the mixing screw along the inner wall in the product chamber to a fixed bearing. To this end the use of a universal joint a non-rotational compensating coupling is known, the known conical screw mixers having the universal joint arranged directly in the product chamber. The universal joint was protected against access of products by an accordion.
The suspension of a non-rotational compensating coupling (in particular a universal joint) directly in the product chamber is disadvantageous, because the compensating coupling is difficult to get at for maintenance. If the accordion was damaged, there was danger that the vessel content would get in contact with the then exposed universal joint, and the contents would thereby become contaminated. Moreover, operational supervision of such a known universal joint was not possible. Disposition of a universal joint inside the product chamber has the further disadvantage that dirt and bacteria corners form, causing an adverse effect on the product being processed in the vessel. Moreover, it was necessary to make the mixing vessel with a universal joint arranged therein relatively large in order to accommodate the entire lower bearing.